The following Xone Series products have K-Slots for Kensington security locks:
XONE:96
XONE:PX5
Xone:DB4
Xone:DB2
Xone:43C
Xone:43
For products that do not feature a K-Slot, it is possible to add one by purchasing a Security Slot Adapter Kit
Do not try to attach a security lock to other slots, e.g chassis louvres designed for ventilation, etc.